Intervertebral cages with integrated expansion and angular adjustment mechanism

ABSTRACT

The embodiments provide various interbody fusion spacers, or cages, for insertion between adjacent vertebrae. The cages may have integrated expansion and angular adjustment mechanisms that allow the cage to change its height and angle as needed, with little effort. The cages may have a first, insertion configuration characterized by a reduced size to facilitate insertion through a narrow access passage and into the intervertebral space. The cages may be inserted in a first, reduced size and then expanded to a second, larger size once implanted. In their second configuration, the cages are able to maintain the proper disc height and stabilize the spine by restoring sagittal balance and alignment. Additionally, the intervertebral cages are configured to be able to adjust the angle of lordosis, and can accommodate larger lordotic angles in their second, expanded configuration. Further, these cages may promote fusion to further enhance spine stability by immobilizing the adjacent vertebral bodies.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. patent application Ser. No. 16/293,483filed Mar. 5, 2019, which claims the benefit of U.S. Patent ApplicationSer. No. 62/639,138 filed Mar. 6, 2018, the disclosure of which ishereby incorporated by reference as if set forth in its entirety herein.

TECHNICAL FIELD

The present disclosure relates to implantable orthopedic devices, andmore particularly to implantable devices for stabilizing the spine. Evenmore particularly, the present disclosure relates to intervertebralcages comprising integrated expansion and angular adjustment mechanismsthat allow expansion of the cages from a first, insertion configurationhaving a reduced size to a second, implanted configuration having anexpanded size. The intervertebral cages are able to adjust angularly,and adapt to lordotic angles, particularly larger lordotic angles, whilerestoring sagittal balance and alignment of the spine.

BACKGROUND

The use of fusion-promoting interbody implantable devices, oftenreferred to as cages or spacers, is well known as the standard of carefor the treatment of certain spinal disorders or diseases. For example,in one type of spinal disorder, the intervertebral disc has deterioratedor become damaged due to acute injury or trauma, disc disease or simplythe natural aging process. A healthy intervertebral disc serves tostabilize the spine and distribute forces between vertebrae, as well ascushion the vertebral bodies. A weakened or damaged disc thereforeresults in an imbalance of forces and instability of the spine,resulting in discomfort and pain. The standard treatment today mayinvolve surgical removal of a portion, or all, of the diseased ordamaged intervertebral disc in a process known as a partial or totaldiscectomy, respectively. The discectomy is often followed by theinsertion of a cage or spacer to stabilize this weakened or damagedspinal region. This cage or spacer serves to reduce or inhibit mobilityin the treated area, in order to avoid further progression of the damageand/or to reduce or alleviate pain caused by the damage or injury.Moreover, these types of cages or spacers serve as mechanical orstructural scaffolds to restore and maintain normal disc height, and insome cases, can also promote bony fusion between the adjacent vertebrae.

However, one of the current challenges of these types of procedures isthe very limited working space afforded the surgeon to manipulate andinsert the cage into the intervertebral area to be treated. Access tothe intervertebral space requires navigation around retracted adjacentvessels and tissues such as the aorta, vena cava, dura and nerve roots,leaving a very narrow pathway for access. The opening to the intradiscalspace itself is also relatively small. Hence, there are physicallimitations on the actual size of the cage that can be inserted withoutsignificantly disrupting the surrounding tissue or the vertebral bodiesthemselves.

Further complicating the issue is the fact that the vertebral bodies arenot positioned parallel to one another in a normal spine. There is anatural curvature to the spine due to the angular relationship of thevertebral bodies relative to one another. The ideal cage must be able toaccommodate this angular relationship of the vertebral bodies, or elsethe cage will not sit properly when inside the intervertebral space. Animproperly fitted cage would either become dislodged or migrate out ofposition, and lose effectiveness over time, or worse, further damage thealready weakened area.

Thus, it is desirable to provide intervertebral cages or spacers thatnot only have the mechanical strength or structural integrity to restoredisc height or vertebral alignment to the spinal segment to be treated,but also be configured to easily pass through the narrow access pathwayinto the intervertebral space, and then accommodate the angularconstraints of this space, particularly for larger lordotic angles.

BRIEF SUMMARY

The present disclosure describes spinal implantable devices that addressthe aforementioned challenges and meet the desired objectives. Thesespinal implantable devices, or more specifically intervertebral cages orspacers, are configured to be expandable as well as angularlyadjustable. The cages may comprise upper and lower plates for bearingagainst endplates of the vertebral bodies, and have integrated expansionand angular adjustment mechanisms that allow the cage to change size andangle as needed, with little effort. In some embodiments, the cages mayhave a first, insertion configuration characterized by a reducedinsertion size to facilitate insertion through a narrow access passageand into the intervertebral space. The cages may be inserted in thefirst configuration and once the cage is implanted, the cage can beexpanded to a second configuration having a larger size than theinsertion size. In their second configuration, the cages are able tomaintain the proper disc height and stabilize the spine by restoringsagittal balance and alignment. Additionally, the intervertebral cagesare configured to be able to adjust the angle of lordosis, and canaccommodate larger lordotic angles, as well as provide pure expansiononly (i.e., height adjustment), or a combination of both angular andheight adjustment, in their second, expanded configuration. Further,these cages may promote fusion to further enhance spine stability byimmobilizing the adjacent vertebral bodies.

According to one aspect of the disclosure, the cages may be manufacturedusing selective laser melting (SLM) techniques, a form of additivemanufacturing. The cages may also be manufactured by other comparabletechniques, such as for example, 3D printing, electron beam melting(EBM), layer deposition, and rapid manufacturing. With these productiontechniques, it is possible to create an all-in-one, multi-componentdevice which may have interconnected and movable parts without furtherneed for external fixation or attachment elements to keep the componentstogether. Accordingly, the intervertebral cages of the presentdisclosure are formed of multiple, interconnected parts that do notrequire additional external fixation elements to keep together.

Even more relevant, cages manufactured in this manner would not haveconnection seams whereas devices traditionally manufactured would havejoined seams to connect one component to another. These connection seamscan often represent weakened areas of the implantable device,particularly when the bonds of these seams wear or break over time withrepeated use or under stress. By manufacturing the disclosed implantabledevices using additive manufacturing, one of the advantages is thatconnection seams are avoided entirely and therefore the problem isavoided.

Another advantage of the present devices is that, by manufacturing thesedevices using an additive manufacturing process, all of the componentsof the device remain a complete construct during both the insertionprocess as well as the expansion process. That is, multiple componentsare provided together as a collective single unit so that the collectivesingle unit is inserted into the patient, actuated to allow expansion,and then allowed to remain as a collective single unit in situ. Incontrast to other cages requiring insertion of external screws or wedgesfor expansion, in the present embodiments the expansion and blockingcomponents do not need to be inserted into the cage, nor removed fromthe cage, at any stage during the process. This is because thesecomponents are manufactured so as to be captured internally within thecages, and while freely movable within the cage, are already containedwithin the cage so that no additional insertion or removal is necessary.

In some embodiments, the cages can have an engineered cellular structureon a portion of, or over the entirety of, the cage. This cellularstructure can include a network of pores, microstructures andnanostructures to facilitate osteosynthesis. For example, the engineeredcellular structure can comprise an interconnected network of pores andother micro and nano sized structures that take on a mesh-likeappearance. These engineered cellular structures can be provided byetching or blasting, to change the surface of the device on the nanolevel. One type of etching process may utilize, for example, HF acidtreatment.

In addition, these cages can also include internal imaging markers thatallow the user to properly align the device and generally facilitateinsertion through visualization during navigation. The imaging markershows up as a solid body amongst the mesh under x-ray, fluoroscopy or CTscan, for example.

Another benefit provided by the implantable devices of the presentdisclosure is that they can be specifically customized to the patient'sneeds. Customization of the implantable devices is relevant to providinga preferred modulus matching between the implant device and the variousqualities and types of bone being treated, such as for example, corticalversus cancellous, apophyseal versus central, and sclerotic versusosteopenic bone, each of which has its own different compression tostructural failure data. Likewise, similar data can also be generatedfor various implant designs, such as for example, porous versus solid,trabecular versus non-trabecular, etc. Such data may be cadaveric, orcomputer finite element generated. Clinical correlation with, forexample, DEXA data can also allow implantable devices to be designedspecifically for use with sclerotic, normal, or osteopenic bone. Thus,the ability to provide customized implantable devices such as the onesprovided herein allow the matching of the Elastic Modulus of ComplexStructures (EMOCS), which enable implantable devices to be engineered tominimize mismatch, mitigate subsidence and optimize healing, therebyproviding better clinical outcomes.

In one exemplary embodiment, an expandable spinal implant is provided.The expandable spinal implant may comprise a housing comprising an upperhousing portion and a lower housing portion. The upper housing portioncan include an upper plate configured for placement against an endplateof a first vertebral body. The lower housing portion can include a lowerplate configured for placement against an endplate of a second, adjacentvertebral body. The upper housing portion can further include uppersidewalls that extend from the upper plate. The lower housing portioncan include lower sidewalls that extend from the lower plate. The upperand lower sidewalls may be configured to slide along one another.

The expandable spinal implant may further include an expansion andangular adjustment mechanism within the housing that is configured toeffect angular adjustment, height adjustment, or a combination of both,of the spinal implant. The expansion and angular adjustment mechanismmay comprise a pair of wedges located at opposite ends of the housing,each wedge having a bearing surface for urging against the sidewalls ofthe upper and lower plates. In addition, the expansion and angularadjustment mechanism may further include a driver component connectingthe wedges together and being configured to pull the wedges towards oneanother upon actuation.

Each of the upper and lower sidewalls may have a sloped profile. Thehousing may further include one or more deformable strips forcontrolling expansion of the intervertebral cage. The bearing surfacesof the wedges may comprise convex surfaces. The wedges may include acentral opening for receiving the driver component therethrough. Thedriver component may include a tool-engaging member configured to coupleto a tool to actuate the driver component. For instance, the driver caninclude an opening for receiving the tool to actuate the drivercomponent. The expansion and angular adjustment mechanism is intended tobe freely held within the housing.

In another exemplary embodiment, an expandable spinal implant isprovided. The expandable spinal implant may comprise a housingcomprising an upper plate configured for placement against an endplateof a first vertebral body, the upper plate having upper sidewallsextending therefrom, and a lower plate configured for placement againstan endplate of a second, adjacent vertebral body, the lower plate havinglower sidewalls extending therefrom.

The expandable spinal implant may further include an expansion andangular adjustment mechanism within the housing and be configured toeffect angular adjustment, height adjustment, or a combination of both,of the spinal implant. The expansion and angular adjustment mechanismmay comprise a pair of wedges located at opposite ends of the housing.Each wedge may have slots on a lower surface for translation along guiderails on the lower plate, such that movement of the wedges causesdistraction or angulation of the plates relative to one another.

The wedges may have slots that are configured to receive projections ofthe upper housing portion to urge the upper plate away from the lowerplate. The lower plate may further include elastically deformable stripsextending from the lower sidewalls. The bearing surfaces of the wedgesmay comprise angled surfaces. The wedges may each include atool-engaging opening. The upper plate may comprise rounded pins forengaging the elastically deformable strips of the lower plate, andfurther include rounded protrusions on an interior of the sidewalls, therounded protrusions engaging the slots on the upper surface of thewedges. The slots on the upper surface of the wedges may be angled.

According to one aspect of the exemplary embodiment, the expandablespinal implant may comprise a porous structure located on the upperplate. According to another aspect, the porous structure may be locatedon the lower plate. In some embodiments, an elastically deformablescreen may be provided extending between the upper and lower plates. Inaddition, teeth may be provided on the lower plate for enhancedanchorage to bone.

In some embodiments, the guide rails may comprise teeth. The wedges mayfurther include click fingers for engaging the teeth of the guide rails.The wedges may be independently movable relative to one another, suchthat movement of one of the wedges effects angular displacement of theupper plate.

In yet another exemplary embodiment, an expandable spinal implant isprovided. The expandable spinal implant may comprise a housingcomprising an upper plate configured for placement against an endplateof a first vertebral body, and a lower plate configured for placementagainst an endplate of a second, adjacent vertebral body. The upperhousing portion and lower housing portion may each have sidewalls thatextend from the upper plate and lower plate, respectively, with each ofthe sidewalls including a set of projections, such as knobs. The housingmay further include a set of brackets. Each bracket may be affixed to anactuator rod that extends out of an end of the housing. The housing mayfurther include a vertical slot that is configured to receive aprojection from each of the upper and lower plates. The projections ofthe sidewalls may reside within angled slots of the bracket. In use,pulling one of the rods effects movement of the knobs relative to theangled slots, which causes angular adjustment of the plates relative tothe housing.

According to an aspect of the present disclosure, each of the sidewallsmay include a set of projections that can be configured as knobs. Eachof the actuator rods may be configured to horizontally translate in onedirection only. The housing may include a top opening to allow the upperplate to extend out of the housing upon expansion, and a bottom openingto allow the lower plate to extend out of the housing upon expansion.The rods can be configured to be independently movable. Additionally,each bracket comprises a pair of angled slots, the angled slots beingangled away from one another.

Although the following discussion focuses on spinal implants, it will beappreciated that many of the principles may equally be applied to otherstructural body parts requiring bone repair or bone fusion within ahuman or animal body, including other joints such as knee, shoulder,ankle or finger joints.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the disclosure. Additional features of thedisclosure will be set forth in part in the description which follows ormay be learned by practice of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate several embodiments of thedisclosure and together with the description, serve to explain theprinciples of the disclosure.

FIG. 1A is a perspective view of an intervertebral cage constructed inaccordance with one example, shown in an insertion configuration;

FIG. 1B is a side elevation view of the intervertebral cage illustratedin FIG. 1A;

FIG. 1C is a perspective view of the intervertebral cage illustrated inFIG. 1A, shown in an expanded configuration;

FIG. 1D is a side elevation view of the intervertebral cage illustratedin FIG. 1C;

FIG. 1E is a sectional side elevation view of the intervertebral cageillustrated in FIG. 1C;

FIG. 1F is a perspective view of the intervertebral cage illustrated inFIG. 1A in an expanded and angularly adjusted configuration;

FIG. 1G is a side elevation view of the intervertebral cage illustratedin FIG. 1E;

FIG. 2A is a lateral view of an intervertebral cage constructed inanother example, showing the intervertebral cage in an insertionconfiguration;

FIG. 2B is an exploded perspective view of the intervertebral cageillustrated in FIG. 2A;

FIG. 2C is a side elevation view of the intervertebral cage illustratedin FIG. 2A shown in an expanded configuration;

FIG. 2D is a lateral view of the intervertebral cage illustrated in FIG.2A shown in an expanded and angularly adjusted configuration;

FIG. 2E is a lateral view of the intervertebral cage illustrated in FIG.2A shown having moved from the expanded and angularly adjustedconfiguration illustrated in FIG. 2D to the expanded configuration;

FIG. 2F is an enlarged view of a guide rail and wedge of theintervertebral cage illustrated in FIG. 2A;

FIG. 2G is a perspective view of the intervertebral cage illustrated inFIG. 2F in an angularly adjusted configuration;

FIG. 3A is a partial cutaway view of an intervertebral cage constructedin accordance with another example, shown in an expanded configuration;

FIG. 3B is a partial cutaway view of the intervertebral cage illustratedin FIG. 3A in an angularly adjusted configuration;

FIG. 3C is a sectional side elevation view of the intervertebral cageillustrated in FIG. 3A, shown in an initial or insertion configuration;

FIG. 3D is a sectional side elevation view of the intervertebral cageillustrated in FIG. 3C, shown during actuation from the insertionconfiguration to an angularly adjusted configuration;

FIG. 3E is a sectional side elevation view of the intervertebral cageillustrated in FIG. 3D, but shown in a fully angularly adjustedconfiguration;

FIG. 3F is a sectional side elevation view of the intervertebral cageillustrated in FIG. 3E, but shown in the expanded configuration;

FIG. 4A is a perspective view of an intervertebral cage constructed inaccordance with another example, configured for anterior lumbarinterbody fusion (ALIF);

FIG. 4B is another perspective view of the intervertebral cageillustrated in FIG. 4A;

FIG. 4C is a side elevation view of the intervertebral cage illustratedin FIG. 4A, showing the cage in the insertion configuration;

FIG. 4D is a side elevation view of the intervertebral cage illustratedin FIG. 4C, but showing the cage in a first angularly adjustedconfiguration;

FIG. 4E is a side elevation view of the intervertebral cage illustratedin FIG. 4D, showing the cage in a second angularly adjustedconfiguration opposite the first angularly adjusted configuration;

FIG. 4F illustrates a principle of the angular adjustment of theintervertebral cage of FIG. 4A;

FIG. 4G is a perspective view of an intervertebral cage constructed inaccordance with another example, configured for lateral lumbar interbodyfusion (LLIF);

FIG. 4H is another perspective view of the intervertebral cageillustrated in FIG. 4G;

FIG. 4I is another perspective view of the intervertebral cageillustrated in FIG. 4G, shown in an initial configuration;

FIG. 4J is a perspective view of the intervertebral cage illustrated inFIG. 4I, but showing the cage in a first angularly adjustedconfiguration;

FIG. 4K is a perspective view of the intervertebral cage illustrated inFIG. 4J, but showing the cage in a second angularly adjustedconfiguration opposite the first angularly adjusted configuration;

FIG. 4L is a sectional side elevation view of the intervertebral cageillustrated in FIG. 4I, shown attached to an insertion instrument;

FIG. 4M is a sectional side elevation view of the intervertebral cageillustrated in FIG. 4J, shown attached to an insertion instrument;

FIG. 4N is a sectional side elevation view of the intervertebral cageillustrated in FIG. 4K, shown attached to an insertion instrument;

FIG. 5A is a perspective view of the intervertebral cage constructed inaccordance with another example;

FIG. 5B is a side elevation view of the intervertebral cage illustratedin FIG. 5A, shown in an unexpanded, insertion configuration;

FIG. 5C is a side elevation view of the intervertebral cage illustratedin FIG. 5B, but shown in an expanded and angularly adjustedconfiguration;

FIG. 5D is another side elevation view of the intervertebral cageillustrated in FIG. 5B, shown in an expanded and angularly adjustedconfiguration;

FIG. 6A is a top perspective rear view of an intervertebral cageconstructed in accordance with another example, shown in an initial orinsertion configuration;

FIG. 6B is a perspective view of an implant assembly including theintervertebral cage illustrated in FIG. 6A and an associated actuatortool;

FIG. 6C is a perspective view of the intervertebral cage illustrated inFIG. 6A shown in an expanded configuration;

FIG. 6D is a sectional perspective view of the intervertebral cageillustrated in FIG. 6A;

FIG. 6E is a bottom view of the intervertebral cage of FIG. 6A;

FIG. 6F is a schematic side elevation view of the intervertebral cageillustrated in FIG. 6A, shown in the initial or insertion configuration;

FIG. 6G is a sectional side elevation view of a lattice structure of theintervertebral cage when the cage is in the initial or insertionconfiguration illustrated in FIG. 6F;

FIG. 6H is a schematic side elevation view of the intervertebral cageillustrated in FIG. 6A, shown in an expanded configuration;

FIG. 6I is a sectional side elevation view of a lattice structure of theintervertebral cage when the cage is in the expanded configurationillustrated in FIG. 6H;

FIG. 6J is a schematic side elevation view of the intervertebral cageillustrated in FIG. 6A, shown in an angularly adjusted configuration;and

FIG. 6K is a sectional side elevation view of a lattice structure of theintervertebral cage when the cage is in the angularly adjustedconfiguration illustrated in FIG. 6J.

DETAILED DESCRIPTION

The present disclosure provides various spinal implant devices, such asinterbody fusion spacers, or cages, for insertion between adjacentvertebrae. The devices can be configured for use in either the cervicalor lumbar region of the spine. In some embodiments, these devices may beconfigured as ALIF cages, or LLIF cages. However, it is contemplatedthat the principles of this disclosure may be equally utilized intransforaminal lumbar interbody fusion (TLIF) devices, posterior lumbarinterbody fusion (PLIF) cages, and oblique lumbar interbody fusion(OLIF) cages.

These cages can restore and maintain intervertebral height of the spinalsegment to be treated, and stabilize the spine by restoring sagittalbalance and alignment. In some embodiments, the cages may haveintegrated expansion and angular adjustment mechanisms that allow thecage to change height and angle as needed, with little effort. The cagesmay have a first, insertion configuration characterized by a first orreduced size or height to facilitate insertion through a narrow accesspassage and into the intervertebral space. In some examples, the firstor reduced height can define the minimum height achievable by the cages.The cages may be inserted in the first, insertion configuration, andthen expanded to a second, expanded configuration once implanted. Thesecond, expanded configuration can be characterized by a second orincreased size or height that is greater than the first or reduced sizeor height. In their second configuration, the cages are able to maintainthe proper disc height and stabilize the spine by restoring sagittalbalance and alignment. Additionally, the plates of the intervertebralcages that contact the vertebral endplates are angularly adjustable.Thus, the intervertebral cages configured to be able to adjust the angleof lordosis or kyphosis, and can accommodate larger lordotic or kyphoticangles in their second, expanded configuration. In this regard,reference to lordotic angles when the cages are configured forimplantation into the lumbar region of the spine can equally apply tokyphotic angles when the cages are configured for implantation into thecervical region of the spine. Further, these cages may promote fusion tofurther enhance spine stability by immobilizing the adjacent vertebralbodies.

Additionally, the implantable devices may be manufactured usingselective laser melting (SLM) techniques, a form of additivemanufacturing. The devices may also be manufactured by other comparabletechniques, such as for example, 3D printing, electron beam melting(EBM), layer deposition, and rapid manufacturing. With these productiontechniques, it is possible to create an all-in-one, multi-componentdevice which may have interconnected and movable parts without furtherneed for external fixation or attachment elements to keep the componentstogether. Accordingly, the intervertebral cages of the presentdisclosure are formed of multiple, interconnected parts that do notrequire additional external fixation elements to keep together.

Thus, devices manufactured in this manner would not have connectionseams whereas devices traditionally manufactured would have joined seamsto connect one component to another. These connection seams can oftenrepresent weakened areas of the implantable device, particularly whenthe bonds of these seams wear or break over time with repeated use orunder stress. By manufacturing the disclosed implantable devices usingadditive manufacturing, connection seams are avoided entirely andtherefore the problem is avoided.

In addition, by manufacturing these devices using an additivemanufacturing process, all of the internal components of the deviceremain a complete construct during both the insertion process as well asthe expansion process. That is, multiple components are providedtogether as a collective single unit so that the collective single unitis inserted into the patient, actuated to allow expansion, and thenallowed to remain as a collective single unit in situ. In contrast toother cages requiring insertion of external screws or wedges forexpansion, in the present embodiments the expansion and blockingcomponents do not need to be inserted into the cage, nor removed fromthe cage, at any stage during the process. This is because thesecomponents are manufactured so as to be captured internally within thecages, and while freely movable within the cage, are already containedwithin the cage so that no additional insertion or removal is necessary.

In some embodiments, the cages can have an engineered cellular structureon a portion of, or over the entirety of, the cage. This cellularstructure can include a network of pores, microstructures andnanostructures to facilitate osteosynthesis. For example, the engineeredcellular structure can comprise an interconnected network of pores andother micro and nano sized structures that take on a mesh-likeappearance. These engineered cellular structures can be provided byetching or blasting, to change the surface of the device on the nanolevel. One type of etching process may utilize, for example, HF acidtreatment.

In addition, these cages can also include internal imaging markers thatallow the user to properly align the cage and generally facilitateinsertion through visualization during navigation. The imaging markershows up as a solid body amongst the mesh under x-ray, fluoroscopy or CTscan, for example.

Another benefit provided by the implantable devices of the presentdisclosure is that they can be specifically customized to the patient'sneeds. Customization of the implantable devices is relevant to providinga preferred modulus matching between the implant device and the variousqualities and types of bone being treated, such as for example, corticalversus cancellous, apophyseal versus central, and sclerotic versusosteopenic bone, each of which has its own different compression tostructural failure data. Likewise, similar data can also be generatedfor various implant designs, such as for example, porous versus solid,trabecular versus non-trabecular, etc. Such data may be cadaveric, orcomputer finite element generated. Clinical correlation with, forexample, DEXA data can also allow implantable devices to be designedspecifically for use with sclerotic, normal, or osteopenic bone. Thus,the ability to provide customized implantable devices such as the onesprovided herein allow the matching of the Elastic Modulus of ComplexStructures (EMOCS), which enable implantable devices to be engineered tominimize mismatch, mitigate subsidence and optimize healing, therebyproviding better clinical outcomes. It should be appreciated throughoutthe description below that the features, structures, and methodsdescribed with respect to one example of an intervertebral cage can beapplied to all other examples of intervertebral cages unless indicatedto the contrary.

Turning now to the drawings, FIGS. 1A to 1F illustrate one example of anexpandable and angularly adjustable intervertebral cage 110 of thepresent disclosure. FIGS. 1A-1B show the intervertebral cage 100 in itsfirst or insertion configuration. The insertion configuration can alsobe referred to as an unexpanded configuration. The intervertebral cage110 includes a housing 112 that is defined by a superior or upperhousing portion 119 and an inferior or lower housing portion 139. Theupper housing portion 119 can include a superior or upper plate 120, andthe lower housing portion 139 can include an inferior or lower plate140. The upper and lower plates 120 and 140, respectively, areconfigured for placement against respective superior and inferiorvertebral bodies. For instance, the upper plate 120 can define an outeror upper bearing surface 121 that is configured to abut an endplate ofthe superior vertebral body. Similarly, the lower plate 140 can definean outer or lower bearing surface 141 that is configured to abut anendplate of the inferior vertebral body. The upper and lower bearingsurfaces 121 and 141 are spaced from each other along a transversedirection T. In one example, the bearing surfaces 121 and 141 can beflat for placement against the endplates. It is understood, of course,that the bearing surfaces 121 and 141 may also be sloped as desired. Forinstance, the bearing surfaces 121 and 141 can be convex and rounded ifdesired. Further, the upper and lower bearing surfaces 121 and 141 canbe defined by flexible slats that are spaced from each other along thelateral direction A, and elongate along the longitudinal direction L.

The intervertebral cage 110 can define a first, leading end 114 withrespect to insertion into an intervertebral disc space defined betweenthe superior and inferior vertebrae. The intervertebral cage 110 canfurther define a second, trailing end 116 opposite the leading end 114along a longitudinal direction L. The longitudinal direction L can beoriented perpendicular to the transverse direction T. Thus, theintervertebral cage 110 can define a leading direction that extends fromthe trailing end 116 toward the leading end 114. Thus, leadingcomponents of the intervertebral cage 110 can be spaced from trailingcomponents of the intervertebral cage in the leading direction. Theintervertebral cage 110 can similarly define a trailing direction thatextends from the leading end 114 toward the trailing end 116.

The upper housing portion 119 can further include upper sidewalls 124that extend from the upper plate 120. For instance, the upper sidewalls124 can extend down from the upper plate 120 along the transversedirection T. The upper sidewalls 124 can be spaced from each other alonga lateral direction A. The lateral direction A can be orientedperpendicular to each of the longitudinal direction L and the transversedirection T. In one example, the transverse direction T can define avertical direction during use. The lateral and longitudinal directions Aand L can define horizontal directions during use. The lower housingportion 139 can include lower sidewalls 144 that extend from the lowerplate 140. For instance, the lower sidewalls 144 can extend up from thelower plate 140 along the transverse direction T. The lower sidewalls144 can be spaced from each other along the lateral direction A. Theupper and lower sidewalls 124 and 144 can be configured to slide alongone another. Thus, the upper and lower plates 120 and 140 can betranslatable and rotatable in relation to each other vertically.

The upper and lower housing portions 119 and 139 can be sloped. That is,the upper and lower housing portions 119 and 139 can define upper andlower sloped engagement surfaces 123 and 143, respectively (see FIG.1D). For instance, one of the upper sloped engagement surfaces 123 canbe a leading upper sloped engagement surface, and the other of the uppersloped engagement surface 123 can be a trailing upper sloped engagementsurface. Similarly, one of the lower sloped engagement surfaces 143 canbe a leading lower sloped engagement surface, and the other of the lowersloped engagement surface 143 can be a trailing lower sloped engagementsurface. In one example, the upper and lower sloped engagement surfaces123 and 143 can be defined by the upper and lower sidewalls 124 and 144,respectively. For instance, the upper and lower sloped engagementsurfaces 123 and 143 can be defined by longitudinally outermost surfacesof the upper and lower sidewalls 124 and 144, respectively.

The engagement surfaces 123 and 143 can be angled, rounded, or otherwiseangularly offset with respect to the transverse direction T as theyextend in the longitudinal direction L. For instance, the leadingengagement surfaces 123 and 143 can flare toward the trailing end asthey extend away from the respective upper and lower plates 120 and 140.Similarly, the trailing engagement surfaces 123 and 143 can flare towardthe leading end as they extend away from the respective upper and lowerplates 120 and 140.

The intervertebral cage 110 can further include at least one elasticallydeformable strip 130 that is configured to control the movement of theupper and lower sidewalls 124 and 144, respectively, relative to oneanother. The elastically deformable strips 130 can be attached to eachof the upper housing portion 119 and the lower housing portion 139. Theelastically deformable strips 130 can have a spring constant that allowsbut resists movement of the upper and lower housing portions 119 and 139relative to each other. In this regard, the elastically deformablestrips 130 can be referred to as spring members that can be configuredas strips or any suitable alternative configuration as desired. Theelastically deformable strips 130 can be located outboard of thesidewalls 124 and 144 with respect to the lateral direction A, as shownin FIG. 1A.

The intervertebral cage 110 can further include an integrated expansionand angular adjustment mechanism that is fully integrated within theintervertebral cage 110. The angular adjustment mechanism can bedisposed between the upper and lower plates 120 and 140, respectively.For instance, the angular adjustment mechanism can be disposed betweenthe upper plate 120 and the lower plate 140 with respect to thetransverse direction T. The angular adjustment mechanism can include adriver component 160 and at least one wedge 150. For instance, theangular adjustment mechanism can include first and second wedges 150 and151, respectively. The first and second wedges 150 and 151 can bedisposed opposite each other with respect to the longitudinal directionL. For instance, the first wedge 150 can be a leading wedge, and thesecond wedge 151 can be a trailing wedge. One or both of the wedges 150and 151 can include an opening or bore 152 that receives the drivercomponent 160. In one example, the bore 152 is a central bore.

The driver component 160 can extend along a central axis. The centralaxis can extend along the longitudinal direction L. In one example, asdescried in more detail below, the driver component 160 is configured tobe actuated or driven so as to draw or pull at least one or both of thewedges 150 and 151 toward the other of the wedges 150 and 151.

The wedges 150 and 151 can have outer engagement surfaces that can beangled, rounded, or otherwise angularly offset with respect to thetransverse direction T as they extend in the longitudinal direction L.For instance, the engagement surfaces can be rounded convex surfaces. Inone example, the leading wedge 150 can define upper and lower engagementsurfaces flare toward the trailing wedge 151 as they extend away fromthe upper and lower plates 120 and 140, respectively. In one example,the upper and lower engagement surfaces of the leading wedge 150 cancombine so as to define a constant and continuously rounded convexengagement surface. Similarly, the trailing wedge 151 can define upperand lower engagement surfaces flare toward the leading wedge 150 as theyextend away from the upper and lower plates 120 and 140, respectively.In one example, the upper and lower engagement surfaces of the trailingwedge 151 can combine so as to define a constantly rounded convexengagement surface.

When the wedges 150 and 151 are drawn, pulled, or otherwise moved towardeach other along the longitudinal direction L, the upper and lowerengagement surfaces of the leading wedge 150 bear against the respectiveleading upper and lower sloped engagement surfaces 123 and 143,respectively. Similarly, the upper and lower engagement surfaces of thetrailing wedge 151 bear against the respective trailing upper and lowersloped engagement surfaces 123 and 143, respectively. The result is thatthe housing 112 expands from the first or insertion configurationillustrated in FIGS. 1A-1B to the second or expanded configurationillustrated in FIGS. 1C-1D. In particular, the wedges 150 and 151 urgethe upper and lower housing portions 119 and 139 to move away from eachother along the transverse direction T. Accordingly, the upper and lowerbearing surfaces 121 and 141 move away from each other along thetransverse direction T. When the intervertebral cage 110 is in the firstor initial configuration, the upper and lower bearing surfaces 121 and141 are spaced apart from each other a first distance along thetransverse direction T. when the intervertebral cage 110 is in thesecond or expanded configuration, the upper and lower bearing surfaces121 and 141 are spaced apart from each other a second distance along thetransverse direction T that is greater than the first distance. As theupper and lower bearing surfaces 121 and 141 move away from each other,the upper and lower sidewalls 124 and 144 slide along each other.

The upper and lower bearing surfaces 121 and 141 define a first relativeangular orientation with respect to each other when the intervertebralcage 110 is in the first or initial configuration. The spring member 130can bias the upper housing portion 119 toward the first relative angularorientation. In one example, the upper and lower bearing surfaces 121and 141 can be oriented parallel to each other in the first relativeangular orientation. The upper and lower bearing surfaces 121 and 141define a second relative angular orientation with respect to each otherwhen the intervertebral cage 110 is in the second or expandedconfiguration. In one example, the second relative angular orientationcan be the same as the first relative angular orientation. Thus, theupper and lower bearing surfaces 121 and 141 can be oriented parallel toeach other in the second relative angular orientation.

In some examples, the intervertebral cage 110 can allow for angularadjustment of the upper and lower plates 120 and 140 relative to oneanother against the force of the spring 130. A drive assembly, includingthe driver component 160 and wedges 150 and 151, can be configured tofloat at least partially or fully within a housing assembly. The housingassembly can include the housing 112, including the upper and lowerplates 120 and 140, and the elastic member, such as the spring 130,connected between the upper and lower plates 120 and 140. The drivercomponent 160 can include a drive end 163 that can be configured toengage an actuation tool that is configured to drive the drivercomponent 160. For instance, the actuation tool can be configured torotate the driver component 160. The drive end 163 can, for instance,define an opening 162 that is configured to receive the actuation tool.The driver component can further include a shaft 164 that supports thefirst and second wedges 150 and 150.

The shaft 164 can be a threaded shaft 164 that has threads 165 at itsdistal end opposite the drive end 163. Thus, the threads 165 can bedisposed at the front end of the shaft 164. The first wedge 150 can beconfigured to threadedly engage the shaft 164. For instance, the firstwedge can carry internal threads 166 that are configured to threadedlymate with the threads 165 of the shaft 164. In one example, the firstwedge 150 can receive a nut 169 that is not rotatable within the firstwedge 150. The nut 169 can define the internal threads 166.Alternatively, the first wedge 150 can define the internal threads 166.Thus, as the shaft 164, and thus the driver component 160, rotates in afirst direction of rotation, the threaded engagement applies a force tothe first wedge 150 toward the second wedge 151, which decreases thelongitudinal distance between the first and second wedges 150 and 151.As the shaft 164, and thus the driver component 160, rotates in anopposite second direction of rotation, the threaded engagement applies aforce to the first wedge 150 away from the second wedge 151, whichincreases the longitudinal distance between the first and second wedges150 and 151.

The second wedge member 151 can be configured to translate freely alongthe shaft 164. In particular, the second wedge member 151 can translatealong the shaft 164 toward and away from the first wedge member 150without actuating the shaft 164. It is recognized, however, that a loadapplied to the plates 120 and 140 will cause the second ramp 151 to abuta stop member 167 of the driver component 160 that prevents the secondwedge 151 from backing off of the shaft 164. Alternatively, the firstwedge 150 can be freely slidable along the shaft 164. Thus, both of thewedges 150 and 151 can be freely slidable along the shaft 164.Alternatively, one of the wedges 150 and 151 can be freely slidablealong the shaft 164, while the other of the wedges 150 and 151 can bethreadedly engaged with the shaft 164. During operation, as the shaft164 is rotated in the first direction of rotation, the first wedge 150is threadedly drawn toward the second wedge 151. However, one or both ofthe first and second wedges 150 and 151 can move toward the other of thefirst and second wedges 150 and 151, depending on the load applied tothe cage 110.

That is, the first wedge 150 can move toward the second wedge 151 alongthe longitudinal direction L while the second wedge 151 remainsstationary with respect to movement along the longitudinal direction L.Alternatively, the second wedge 151 can move toward the first wedge 150along the longitudinal direction L while the first wedge 150 remainsstationary with respect to movement along the longitudinal direction L.Alternatively still, each of the first and second wedges 150 and 151 canmove toward the other of the first and second wedges 150 and 151. Insome examples, one of the first and second wedges 150 and 151 can move agreater distance than the other of the first and second wedges 150 and151.

In particular, a compressive load applied to one end of the cage 110will cause the plates 120 and 140 to apply a compressive force to thecorresponding wedge. Thus, a compressive load applied to the leading end114 of the cage 110 causes the leading ends of the plates 120 and 140 toapply a compressive load to the leading wedge 150. As a result,actuation of the driver component 160 in the first direction can causethe trailing wedge 151 to move toward the leading wedge 150, as theleading wedge 150 is maintained stationary due to frictional forcesbetween the leading wedge 150 and the upper and lower plates 120 and 140resulting from the compression of the plates 120 and 140 against theleading wedge. Accordingly, the cage 110 will angulate such that thetrailing end 116 has a height greater than the leading end 114.

Conversely, a compressive load applied to the trailing end 116 of thecage 110 causes the trailing ends of the plates 120 and 140 to apply acompressive load to the trailing wedge 151. As a result, actuation ofthe driver component 160 in the first direction can cause the leadingwedge 150 to move toward the trailing wedge 151, as the trailing wedge151 is maintained stationary due to frictional forces between thetrailing wedge 151 and the upper and lower plates 120 and 140 resultingfrom the compression of the plates 120 and 140 against the trailingwedge 151. Accordingly, the cage 110 will angulate such that the leadingend 114 has a height greater than the trailing end 116 (see FIG. 1F).

Alternatively still, if the load applied to the cage 110 is uniform, thefirst and second wedges 150 and 151 can travel equal distances along thelongitudinal direction L, and the relative orientation of the upper andlower plates 120 and 140 prior to expansion will equal the relativeorientation of the upper and lower plates 120 and 140 after expansion.

Thus, it should be appreciated that the wedges 150 and 151 can adopt arelative position that is based on a load distribution on the plates 120and 140. The load distribution can be applied by the anatomical loadonce the intervertebral cage 110 has been implanted in theintervertebral space. Depending on the orientation of the load,expansion of the cage 110 along the transverse direction T will stop onone side and can be continued on the other side as the cage 110 isexpanded until the plates 120 and 140 are in complete contact with therespective vertebral endplates. Thus, the intervertebral cage 110 may beangularly adjustable and expandable with an integrated expansion andangular adjustment mechanism that is entirely contained within thehousing 112. In this regard, the second relative angular orientation canbe different than the first relative angular orientation. It iscontemplated that normal anatomical loads will not cause the wedges 150and 151 to move away from each other along the longitudinal direction L.

The driver component 160 may have a tool-engaging opening 162 to attachto a tool for actuation. The tool can be configured to drive the drivercomponent 160 to draw the wedges 150 and 151 toward each other to expandthe implant, and can further be configured to cause the wedges 150 and151 to separate from each other. It is contemplated that any type ofdriving mechanism may be employed for the driver component 160. Forexample, one may be a threaded screw or bolt mechanism, while in anotherexample the driving mechanism may be a push-pull mechanism. In anotherexample, the driving mechanism may employ a pulley type mechanism, andin still another example, the driving mechanism may employ a tie wrap orelastically deformable capture mechanism.

FIGS. 2A to 2G illustrate another example of an expandable and angularlyadjustable intervertebral cage 210 of the present disclosure. Like theintervertebral cage 110 described above with respect to FIGS. 1A-1F,this intervertebral cage 210 can include a housing 212 that, in turn,includes an upper housing portion 219 and a lower housing portion 239.The upper housing portion 219 includes an upper plate 220 that definesan upper bearing surface 221. The lower housing portion 239 includes alower plate 240 that defines a lower bearing surface 241. The upper andlower plates 220 and 240, respectively, are configured for placementagainst endplates of a pair of adjacent vertebral bodies in anintervertebral space that is defined between the vertebral bodies. Inone example, the bearing surfaces 221 and 241 can be flat for placementagainst the endplates. It is understood, of course, that the bearingsurfaces 221 and 241 may also be sloped as desired. For instance, thebearing surfaces 221 and 241 can be convex and rounded if desired.Further, the upper and lower bearing surfaces 221 and 241 can be definedby flexible slats that are spaced from each other along the lateraldirection A, and elongate along the longitudinal direction L.

The upper housing portion 219 can include upper sidewalls 224 thatextend down from the upper plate 220, and the lower housing portion 239can include lower sidewalls 244 that extend up from the lower plate 240.The sidewalls 224 and 244 are configured to slide along each other, andcan allow the upper and lower housing portions 219 and 239, and thus theupper and lower plates 220 and 240, to translate and rotate in relationto each other vertically, as explained below. Further, as shown in FIG.2B, the upper housing portion 219 can include a plurality of pairs ofprotrusions 228 a-228 c that extend out from the upper sidewalls 224proximate to a lowermost end of the upper sidewalls 224. The protrusions228 a-228 c can be configured as rounded knobs or protrusions, or anyalternative geometry as desired. The first protrusions 228 a can bepositioned as first outer projections, the second protrusions 228 b canbe positioned as second outer projections, and the third protrusions 228c can be configured as middle outer projections that are disposedbetween the first and third outer projections along the longitudinaldirection L.

One of the upper and lower housing portions 219 and 239 can include atleast one seat 236, and the other of the upper and lower housingportions 219 and 239 can include a spring member 230 having a free endthat bears against the seat. In one example, the lower housing portion239 can include the spring member 230 that extends along one or both ofthe lower sidewalls 244. The upper plate 220 can include the at leastone seat that extends out from the upper sidewall 224. The at least oneseat can be in in the form of semi-circular or rounded pins 226, or anysuitable alternative geometry, that extends out from the upper sidewallsproximate to an upper end of the upper sidewalls 224. The combination ofthe elastically deformable spring 230 and the pins 226 form an elasticinterconnection between the upper and lower housing portions 219 and239, and thus also between the upper and lower plates 220 and 240, asshown in FIG. 2A.

The intervertebral cage 210 can further include an integrated expansionand angular adjustment mechanism that is fully integrated within theintervertebral cage 210. The angular adjustment mechanism can bedisposed between the upper and lower plates 220 and 240, respectively.For instance, the angular adjustment mechanism can be disposed betweenthe upper plate 220 and the lower plate 240 with respect to thetransverse direction T. The angular adjustment mechanism can include atleast one wedge. For instance, the angular adjustment mechanism caninclude first and second wedges 250 and 251, respectively. The first andsecond wedges 250 and 251 can be disposed opposite each other withrespect to the longitudinal direction L. It should thus be appreciatedthat the intervertebral cage 210 can consist of four (4) separatecomponents that can be manufactured or SLM printed in one run. The fourseparate components can be defined by the upper hosing portion 219, thelower housing portion 239, the first wedge 250, and the second wedge251.

The first wedge 250 can be aligned with a first portion of the upperplate 220 along the transverse direction T. Similarly, the second wedge251 can be aligned with a second portion of the upper plate 220 alongthe transverse direction T. Because the wedges 250 and 251 are movablealong the longitudinal direction L, the location of the first and secondportions of the upper plate 220 can likewise vary as the wedges 250 and251 move.

The wedges 250 and 251 can have engagement surfaces that can be angled,rounded, or otherwise angularly offset with respect to the transversedirection T as they extend in the longitudinal direction L. Forinstance, the engagement surfaces can be straight linear surfaces. Inone example, each wedge 250 and 251 can include a pair of laterallyopposed sloped slots 258 that define the engagement surfaces. The slopedslots 258 of the first wedge 250 can be sloped toward the second wedge251 as they extend away from the upper plate 220 along the transversedirection T. Similarly, the sloped slots 258 of the second wedge 251 canbe sloped toward the first wedge 250 as they extend away from the upperplate 220 along the transverse direction T. As will be appreciated fromthe description below, the sloped slots 258 of the first and secondwedges 250 and 251 are configured to receive the protrusions 228 a and228 b, respectively, so as to cause at least a portion of the firstplate 220 to move away from the second plate 240 along the transversedirection T, thereby expanding and/or angulating the cage 210. The lowerplate 240 can remain stationary during movement of the upper plate 220.

The lower plate 240 may include at its far longitudinal ends a pair ofstop members 246 that can prevent the wedges 250 and 251 from backingout of the housing 212. The lower housing portion 239 can furtherinclude at least one guide rail 248 that is configured to be received bya corresponding channel 256 that extends through the wedges 250 and 251along the longitudinal direction L. The at least one guide rail 248 canbe oriented along the longitudinal direction L. Further, the at leastone guide rail 248 can extend along a transverse inner surface of thelower plate 240. In one example, the lower housing portion 239 caninclude first and second guide rails 248 that are spaced from each otheralong the lateral direction A and are received in respective channels256 of the wedges 250 and 251. The guide rails 248 can have outwardlyprojecting teeth 272 (see FIG. 2F). Similarly, the wedges 250 caninclude at least one complementary finger 274 in the channels 256 thatis configured to engage and interlock with the teeth 272 of the guiderails 248 (see FIG. 2F).

During operation, the wedges 250 can be deployed individually and areconfigured to slide individually along the guide rails 248 along thelongitudinal direction L. The sloped slots 258 of the first wedge member250 receive the first protrusions 228 a, and the sloped slots 258 of thesecond wedge member 251 receive the third protrusions 228 b. Thus, asshown in FIG. 2C, as each of the members 250 and 251 translateslongitudinally toward the other wedge member 250 and 251, the engagementsurfaces of the wedge members 250 defined by the sloped slots 258 bearagainst the first and second protrusions 228 a and 228 b, respectively,which urges the upper housing portion 219, and thus the upper plate 220,to move away from the lower housing portion 239, and thus the lowerplate 240, along the transverse direction T.

The lower housing portion 239 can define a transverse slot 253 thatextends into each of the lower sidewalls 244 (see FIG. 2B). Thetransverse slots 253 are configured to receive the third protrusion 228c. Alternatively, the upper housing portion 219 can define thetransverse slot 253 that extends into each of the upper sidewalls, andthe third protrusion 228 c can be carried by the lower housing portion239. The third protrusions 228 c can ride along the transverse slots 253as the upper housing portion 219 moves relative to the lower housingportion 239 along the transverse direction. It should be appreciatedthat the middle protrusion 228 c travels along the vertical ortransverse direction T in the transverse slot 25, while the first andsecond protrusions 228 a and 228 b ride in the sloped slots 258 that areangled with respect to the transverse direction T. As illustrated inFIGS. 2A and 2C, the first relative angular orientation of the plates220 and 240 prior to expansion can equal the second relative angularorientation of the plates 220 and 240 after expansion.

Referring now to FIG. 2D, the wedges 250 and 251 can be separatelydeployable and independently movable. Independently moving one of thewedges 250 and 251 can cause angular adjustment of the intervertebralcage 210. In particular, independently moving the wedges 250 and 251 cancause angular adjustment of the upper plate 220 with respect to thelower plate 240. For instance, by moving the first wedge 250 toward thesecond wedge 251 while maintaining the second wedge 251 stationary, theupper plate 220 may be angularly adjusted. In particular, the firstportion of the upper plate 220 can move away from the lower plate 240along the transvers direction T relative to the second portion of theupper plate 220. It should be appreciated that the upper plate 220 canangulate both when the second wedge 251 remains stationary, or when thefirst wedge 250 translates along the longitudinal direction at adisproportionate amount with respect to the translation of the secondwedge 251 (both referred to as movement of the first wedge relative tothe second wedge along the longitudinal direction L). Translation ofboth wedges 250 and 251 a disproportionate amount can cause the cage 210to both expand along the transverse direction T and angulate. It shouldbe further appreciated that the upper plate 220 can angularly adjustabout the middle protrusion 228 c as it is disposed in the transverseslot 253. Thus, the middle protrusion 228 c can define a fulcrum forangular movement of the upper plate 220. Accordingly, the secondrelative angular orientation of the first and second plates 220 can bedifferent than the second relative angular orientation of the first andsecond plates 220. It should be appreciated that an opposite angularadjustment can also be achieved by moving the second wedge 250 relativeto the first wedge along the longitudinal direction L.

If it is desired to achieve the second relative angular orientationequal to the first relative angular orientation, the second wedge 251can be moved longitudinally toward the first wedge 250, which urges thesecond location of the upper plate 220 to move relative to the firstlocation of the upper plate 220 away from the lower plate 240 along thetransverse direction. This causes the upper plate 220 to angulate aboutthe middle protrusion 228 c until the first and second portions of theupper plate 220 are equally spaced from the lower plate 240 along thetransverse direction T. The resultant intervertebral cage 210 can haveparallel upper and lower plates 220 and 240 in its second or expandedconfiguration. The first and second wedges 250 and 251 can be moved awayfrom each other so as to urge the upper plate 220 to move toward thelower plate 240 along the transverse direction T, if it is desired tocollapse the intervertebral cage 210. The sidewalls 224 and 244 canslide along each other as the cage 210 expands and angulates.

Referring now to FIGS. 2F and 2G, and as described above, the housing212 can define the guide rails 248, and the first and second wedges 250and 251 can define the channels 256 that receive and ride along theguide rails 248 as the first and second wedges 250 and 251 translatelongitudinally. The finger 274 can be a click finger 274 that isconfigured to ride along the teeth 272 as the wedges 250 and 251 movetoward one another along the longitudinal direction L. However, thefinger 274 can interlock with the teeth 272 so as to prevent movement ofthe first and second wedge members 250 and 251 away from each other inresponse to anatomical loading. Alternatively, the finger 274 caninterlock with the teeth 272 so as to prevent movement of the first andsecond wedge members 250 and 251 both toward and away from each other.An implant assembly can include a bayonet type actuation instrument 290that is insertable be inserted into a tool-engaging opening 262 ofeither wedge 250. The instrument 290 can be configured to urge thefingers 274 away from the teeth 272, thereby disengaging the fingers 274from the teeth 272. Thus, engagement between the fingers 274 and theteeth 272 no longer prevents relative movement of the wedges 250 and 251away from each other and, in some examples, toward each other. In oneexample, turning a bayonet-shaped end of the tool (for instance 90degrees) can cause the fingers 274 to be urged away from the teeth 272,thereby unlocking the wedge 250 from the teeth 274. Releasing theinstrument 290 can cause the fingers 274 to again engage the teeth 272,thereby locking the wedge 250 in place relative to the rails 248.

It is appreciated that the spring member 230 can provide a pre-tensionthat connect the upper housing portion 219 and the lower housing portion239 together. The spring member 230 can be shaped to allow both verticaland angular movement of the type described above against thepre-tensioned spring force. The spring members 230 can be designed toonly allow the movements described above.

FIGS. 3A to 3F illustrate yet another example of an expandable andangularly adjustable intervertebral cage 310 of the present disclosure.The intervertebral cage 310 can include an outer housing 312 and upperand lower housing portions 319 and 339 that are movable within the outerhousing 312. The outer housing 312 can have an open top and bottom toaccommodate movement of the upper and lower housing portions 319 and339. The upper housing portion 319 can include an upper plate 320 andupper sidewalls 324 that extend down from the upper plate 320 along thetransverse direction T. The lower housing portion 339 can include alower plate 340 and lower sidewalls 344 that extend up from lower plate340 along the transverse direction T. The upper and lower plates 320 and340, respectively, can be configured to be placed against endplates of apair of adjacent vertebral bodies. The upper plate 320 can define anupper bearing surface configured to abut a vertebral endplate of asuperior vertebral body, and the lower plate 340 can define a lowerbearing surface configured to abut a vertebral endplate of an inferiorvertebral body. In one example, the bearing surfaces can besubstantially flat. It is understood, of course, that the bearingsurfaces can be shaped surfaces, such as convex, and rounded, ifdesired.

FIG. 3A shows the intervertebral cage 310 in an expanded configurationwhereby a distance between the upper and lower plates 320 and 340 hasincreased along the transverse direction T. FIG. 3B shows the sameintervertebral cage 310 in an expanded, and angularly adjusted,configuration, whereby a relative angular orientation between the upperand lower plates 320 and 340 have been changed.

With reference to FIGS. 3A-3B, the intervertebral cage 310 furtherincludes an expansion and angular adjustment mechanism disposed betweenthe upper and lower plates 320 and 340 with respect to the transversedirection T. The expansion and angular adjustment mechanism can includefirst and second brackets 350 and 351 that are disposed in the outerhousing 312. The first and second brackets 350 and 351 can be configuredas brackets in one example. The first bracket 350 can be aligned withboth a first portion of the upper plate 320 and a first portion of thelower plate 340 along the transverse direction T. Similarly, the secondbracket 351 can be aligned with a second portion of the upper plate 320and a second portion of the lower plate 340 along the transversedirection T. Because the brackets 350 and 351 are movable along thelongitudinal direction L as described below, the location of the firstand second portions of the upper and lower plates 320 and 340 canlikewise vary as the brackets 350 and 351 move.

Each of the first and second brackets 350 and 351 can have engagementsurfaces that can be angled, rounded, or otherwise angularly offset withrespect to the transverse direction T as they extend in the longitudinaldirection L. For instance, the engagement surfaces can be straightlinear surfaces. In one example, each bracket 350 and 351 can include apair of laterally opposed sloped upper slots 352 and laterally opposedlower slots 353 that define the engagement surfaces. The upper slopedslots 352 of the first bracket 350 can be sloped away from the secondbracket 351 as it extends away from the upper plate 320 along thetransverse direction T. The upper sloped slots 352 of the second bracket351 can be sloped away from the first bracket 350 as it extends awayfrom the upper plate 220 along the transverse direction T. The lowersloped slots 353 of the first bracket 350 can be sloped away from thesecond bracket 351 as it extends away from the lower plate 340 along thetransverse direction T. The lower sloped slots 353 of the second bracket351 can be sloped away from the first bracket 350 as it extends awayfrom the lower plate 340 along the transverse direction T. As will nowbe described, the sloped slots 258 and 259 are configured to receiveprojections of the upper and lower plate members 319 and 339 that urgethe upper and lower plates 320 and 340 to move relative to each otheralong the transverse direction T, thereby expanding and/or angulatingthe cage 310.

In particular, the upper plate portion 319 can include first and secondpairs of upper protrusions 326. The upper protrusions 326 can extend outfrom the upper sidewalls 324. Each of the pairs can be spaced from eachother along the longitudinal direction L. Further, the upper protrusions326 of each pair can be opposite each other along the lateral directionA. The upper protrusions 326 can be configured as knobs in one example.The protrusions 326 are sized to be received in the upper sloped slots352, and freely slidable in the upper sloped slots 352. The first pairof upper protrusions 326 are configured to ride in the upper slots ofthe first bracket 350. The second pair of upper protrusions 326 areconfigured to ride in the upper slots of the second bracket 351.

Similarly, the lower plate portion 339 can include first and secondpairs of lower protrusions 346. The lower protrusions 346 can extend outfrom the lower sidewalls 344. Each of the pairs can be spaced from eachother along the longitudinal direction L. Further, the lower protrusions346 of each pair can be opposite each other along the lateral directionA. The lower protrusions 346 can be configured as knobs in one example.The lower protrusions 346 are sized to be received in the lower slopedslots 353, and freely slidable in the lower sloped slots 353. Forinstance, the first pair of lower protrusions 346 are configured to bereceived in the lower sloped slots 353 of the first bracket 350. Thesecond pair of lower protrusions 346 are configured to be received inthe lower sloped slots 353 of the second bracket 351. Thus, the upperand lower protrusions 326 and 346 can define engagement surfaces thatride along respective engagement surfaces in the upper and lower slots352 and 353 so as to cause the upper and lower housing portions 319 and339 to move relative to each other along the transverse direction T.

The outer housing 312 can define a pair of transverse side channels 318that are aligned in the lateral direction A with one of the protrusions326 and 346 that extend through one of the brackets 350 and 351,illustrated as the first bracket 350. Thus, the upper and lowerprotrusions 326 and 346 that extend though the respective upper andlower slots 352 and 353 of the first bracket 350 can further extend intothe channels 318. Because the side channels 318 are elongate along thetransverse direction T, the engagement of the side channels 318 with therespective protrusions 326 and 346 prevents or limits longitudinalmovement of the upper and lower plates 320 and 340. In one example, theouter housing 312 does not define any side channels 318 that receive theprotrusions of the second bracket 351.

The intervertebral cage 310, and in particular the expansion and angularadjustment mechanism, can include a first actuation rod 370 that istranslatably fixed to the first bracket 350 and longitudinallytranslatable with respect to the second bracket 351, and a secondactuation rod 380 that is translatably fixed to the second bracket 351and longitudinally translatable with respect to the first bracket 350.The first and second rods 370 and 380 can extend gripping ends thatextend longitudinally out from the outer housing 312. Thus, the firstbracket 350 moves longitudinally with the first actuation rod 370.Similarly, the second bracket 351 moves longitudinally with the secondactuation rod 380. In one example, the first and second actuation rods370 and 380 can be configured as pull rods that are configured to bepulled longitudinally to effect sliding longitudinal movement of thebrackets 350 and 351.

As described above, first ones of the upper and lower protrusions 326and 346 of the upper housing member 319 and lower housing member 339 areslidable in the upper and lower sloped slots 352 and 353, respectively,of the first bracket 350. This causes the distance between the firstportions of the first and second plates 320 and 340 to change along thetransverse direction. For instance, as the first bracket 350 is movedaway from the second bracket 351, the first protrusions 326 and 346 pushagainst the upper and lower housing portions 319 and 339. Thus, thedistance between the first portions of the first and second plates 320and 340 increases along the transverse direction T. As the first bracket350 is moved toward the second bracket 351, the distance between thefirst portions of the first and second plates 320 and 340 decreasesalong the transverse direction T.

Similarly, second ones of upper and lower protrusions 326 and 346 of theupper housing member 319 and lower housing member 339 are slidable inthe upper and lower sloped slots 352 and 353, respectively, of thesecond bracket 351. This causes the distance between the second portionsof the first and second plates 320 and 340 to change along thetransverse direction T. For instance, as the second bracket 351 is movedaway from the first bracket 350, the second protrusions 326 and 346 pushagainst the upper and lower housing portions 319 and 339. Thus, thedistance between the second portions of the first and second plates 320and 340 increases along the transverse direction T. As the secondbracket 350 is moved toward the first bracket 350, the distance betweenthe second portions of the first and second plates 320 and 340 decreasesalong the transverse direction T.

The first and second actuation rods 370 and 380 are configured to movelongitudinally relative to the outer housing 312. Longitudinal movementof the rods 370 and 380 causes the respective brackets 350 and 351affixed to the rod to be likewise moved longitudinally. In each of thebrackets 350 are upper and lower angled slots 352 and 353, as describedabove. The slots 352 and 353 are integrated above and below each other,and angled in opposite directions. The slots 352 and 353 of the firstbracket 350 are mirrored and can be deployed independently of the slots352 and 353 of the second wedge member 351, and vice versa. Themechanism within the outer housing 312 enables the upper and lowerplates 320, 340 to slide vertically at the hinge or pivot joints definedby the knobs 326, 346 within the angled slots 352. Further, the firstprotrusions 326 and 346 can slide within the transverse side channel 318of the outer housing 312, while the second protrusions 326 and 346 canslide only within the respective slots of the second bracket 351.

A method of actuating the intervertebral cage 310 will now be describedwith reference to FIGS. 3C-3F. In a starting position illustrated inFIG. 3C, with the intervertebral cage 310 in its first or insertionconfiguration, the upper and lower projections 326 and 346 are in thetransverse innermost position of the respective slots 352 and 353,respectively. Further, the first projections 326 and 346 are in theirrespective transverse innermost positions in the side channels 318.Referring to FIG. 3D, when the second rod 380 is actuated to move thesecond bracket 351 longitudinally away from the first bracket 350, thesecond upper and lower protrusions 326 and 346 are forced upward anddownward, respectively, by the angled slots 352 and 353 of the secondbracket 351. Thus, the second portions of the upper and lower plates 320and 340 are moved away from each other along the transverse direction T.The first portions of the upper and lower plates 320 and 340 can remainstationary with respect to relative movement along the transversedirection T, thereby effecting expansion and angular adjustment of theintervertebral cage 310 as shown in FIG. 3E. In particular, respectiveangular orientations of the upper and lower plates 320 and 340 canchange with respect to the outer housing 312. Thus, it will be furtherappreciated that the second relative angular orientation of the cage 310can be different than the first angular orientation of the cage 310.

Referring now to FIG. 3F, when the first rod 370 is actuated to move thefirst bracket 350 longitudinally away from the second bracket 351, thefirst upper and lower protrusions 326 and 346 are forced upward anddownward, respectively, by the angled slots 352 and 353 of the firstbracket 350. Thus, the first portions of the upper and lower plates 320and 340 are moved away from each other along the transverse direction T.The second portions of the upper and lower plates 320 and 340 can remainstationary with respect to relative movement along the transversedirection T. The first portions of the upper and lower plates 320 and340 can expand vertically to a position whereby that the first andsecond plates 320 and 340 are in the same relative angular orientationas before expansion. Thus, the first relative angular orientation can beequal to the second relative angular orientation. Alternatively, thefirst portions of the upper and lower plates 320 and 340 can expandvertically to a position whereby that the first and second plates 320and 340 are in a different relative angular orientation as beforeexpansion.

Movement of the rods 370 and 380 can be restricted by the outer housing312 to movement along the longitudinal direction L. Because theengagement between the first upper and lower protrusions 326 and 346 inthe vertical channel 318, the upper and lower housing portions 319 and339 are prevented from moving longitudinally. Further, the first upperprotrusion 326 can define a fulcrum about which the second portion ofthe upper plate 320 can angulate when the second bracket 351 is movedaway from the first bracket 350.

FIGS. 4A to 4N illustrate even still more examples of expandable andangularly adjustable intervertebral cages 410, 410′ of the presentdisclosure. FIGS. 4A to 4F show an intervertebral cage 410 configuredfor anterior lumbar interbody fusion (ALIF), while FIGS. 4G to 4N showthe same intervertebral cage 410′ but configured for lateral lumbarinterbody fusion (LLIF). The intervertebral cage 410 of FIGS. 4A to 4Fshown includes features of the intervertebral cage 210 described above,such as the internal mechanism for expansion and angular adjustment. Asshown, the cage 410 can include a first or leading end 414 and a secondor trailing end 416 opposite the leading end 414 along the longitudinaldirection L. The cage 410 can include a housing 412 that includes anupper housing portion 419 and a lower housing portion 439. The upperhousing portion 419 can include an upper plate 420 and upper sidewalls424 that extend down from the upper plate 420 along the transversedirection T. The lower housing portion 439 can include a lower plate 440and lower sidewalls 444 that extend up from the lower plate 440 alongthe transverse direction T. The intervertebral cage 410 can furtherinclude a pair of wedges 450 and 451 that translate on a guide rail 448located on an inner transverse surface of the lower plate 440, and canmove in a manner as described above for intervertebral cage 210.However, the intervertebral cage 410 can further include porousstructures 422 on one or both of the upper plate 420 and the lower plate440 that facilitate cellular activity and bony ingrowth. Thus, theporous structures 422 can define at least a portion of the upper andlower bearing surfaces of the upper and lower plates 420 and 440,respectively.

Referring to FIGS. 4C to 4E, the longitudinal or horizontal movement ofthe wedges 450 and 451 (independently of one another) effects theexpansion in height and the angular adjustment of the plates 420 and 440relative to one another, as represented by the drawing in FIG. 4F and asdescribed above with respect to the intervertebral cage 210. FIG. 4Cshows the intervertebral cage 410 in a first or unexpanded insertionconfiguration and attached to an insertion and actuation instrument 490.FIG. 4D shows the first wedge 450 longitudinally moved towards thesecond wedge 451 using the attached instrument 490, causing the cage 410to expand and also be angularly adjusted. FIG. 4E shows the second wedge451 longitudinally moved towards the first wedge 450 using the attachedinstrument 490, causing the cage 410 to expand and also be oppositelyangularly adjusted. Thus, it should be appreciated that the independentmovement of the wedges 450 and 451 allows the user to adjust the angleof the cage 410 between a first angle whereby the upper plate 420 issloped toward the lower plate in a first longitudinal direction and asecond angle whereby the upper plate 420 is sloped toward the lowerplate 440 in a second longitudinal direction that is opposite the firstlongitudinal direction, as shown schematically in FIG. 4F.

In general, the intervertebral cage 410 of the present disclosure may beconfigured for anterior lumbar interbody fusion (ALIF). The cage 410 canbe dimensioned as desired. In one example, the cage 410 may havedimensions ranging from 34×25; 37×27; 40×29; and 45×32 mm. Thus, thelongitudinal length of the cage 410 can range from approximately 34 mmand approximately 45 mm (with approximately 1 mm incrementstherebetween). The lateral width of the cage 410 can range fromapproximately 25 mm to approximately 32 mm (with approximately 1 mmincrements therebetween). The height of the cage 410 along thetransverse direction from the upper bearing surface to the lower bearingsurface can range from approximately 8 mm to approximately 20 mm (withapproximately 1 mm increments therebetween). The term “approximate”recognizes manufacturing tolerances and other potential variations, andincludes plus or minus 10% of the stated number. The angular adjustmentmay range from and to approximately 0 degrees, approximately 5 degrees,approximately 10 degrees, approximately 15 degrees, and approximately 20degrees. It is contemplated that the cage 410 may allow a small stepadjustment, and be reversible during the procedure. The cage 410 may beprinted in one run, with deployment of the wedges 450 being independentand with the use of the dedicated actuator/insertion instrument 490.

FIGS. 4G to 4N illustrate an intervertebral cage 410′ that is similar tothe intervertebral cage 410 previously described above, but configuredfor lateral lumbar interbody fusion (LLIF). While the cage 410 can beconfigured to angulate in the sagittal plane once implanted into theintervertebral disc space, the cage 410′ can be configured to angulatein the coronal plane when implanted into the intervertebral disc space.The cage 410′ is otherwise the same as cage 410, and therefore sharesimilar features as represented by the same reference number followed bythe symbol “′”. As shown, the cage 410′ may include a housing 412′ that,in turn, includes an upper housing portion 419′ and a lower housingportion 439′. The upper housing portion 419′ includes an upper plate420′ and upper sidewalls 424′ that extend down from the upper plate 420′along the transverse direction T. The lower hosing portion 439′ includesa lower plate 440′ and lower sidewalls 444′ that extend up from thelower plate 440′ along the transverse direction T. The intervertebralcage 410′ can include a pair of wedges 450′ and 451′ that translate on aguide rail 448′ located on the inner transverse surface of the lowerplate 440′, and move in a manner similar to what was described above forintervertebral cages 210 and 410. The upper housing portion 419′ canalso have porous structures 422′ on the upper plate 420′ may also haveporous structures 422′ that facilitate cellular activity and bonyingrowth. Thus, at least a portion of the upper bearing surface of theupper plate 420′ can be defined by the porous structures 422′.

As shown in FIGS. 4I to 4N, the lateral or horizontal movement of thewedges 450′ (independently of one another) effects the expansion inheight and the angular adjustment of the plates 420′, 440′ relative toone another. FIGS. 4I and 4L show the intervertebral cage 410′ in afirst or unexpanded insertion configuration and attached to aninsertion/actuation instrument 490. The wedges 450′ and 451′ of theintervertebral cage 410 can be longitudinally moved towards one anotherindependently in FIGS. 4J and 4M using the attached instrument 490,causing the cage 410′ to expand and also be angularly adjusted in themanner described above. The independent movement of the wedges 450′ and451′ allows the user to adjust the angle of the cage 410′, as shown inFIGS. 4K and 4N.

In general, the intervertebral cage 410′ of the present disclosure maybe configured for lateral lumbar interbody fusion (LLIF), and in oneexample, may have a longitudinal dimension ranging from approximately 40mm to approximately 60 mm, including approximately 40 mm, approximately45 mm, approximately 50 mm, approximately 55 mm, and approximately 60mm. The cage 410 can have a lateral dimension that ranges fromapproximately 22 mm to approximately 26 mm, including approximately 22mm and approximately 26 mm. The age can have a height that ranges fromapproximately 8 mm to approximately 16 mm (with approximately 1 mmincrements therebetween). The angular adjustment of the cage 410′ mayrange from approximately 0 degrees to approximately 16 degrees,including approximately 0 approximately, approximately 8 degrees, andapproximately 16 degrees, as measured by an angle defined by the upperand lower plates 420′ and 440′. It is contemplated that the cage 410′may allow a small step adjustment, and be reversible during theprocedure. The cage 410′ may be printed in one run, with deployment ofthe wedges 450′ being independent and with the use of the dedicatedactuator/insertion instrument 490.

FIGS. 5A to 5D illustrate even further still another example of anexpandable and angularly adjustable intervertebral cage 510 of thepresent disclosure which utilizes many of the same features of theexamples described above. As shown, the cage 510 can include a housing512 that includes an upper housing portion 519 and a lower housingportion 539. The upper housing portion 519 can include an upper plate520 and upper sidewalls 524 that extend down from the upper plate 520.The lower housing portion 539 can include a lower plate 540 and lowersidewalls 544 that extend up from the lower plate 540. Theintervertebral cage 510 can further include a pair of first and secondwedges 550 and 551 that translate independently of each other on a guiderail 548 located on an inner transverse surface of the lower plate 540.The wedges 550 and 551 can move in the manner described above withrespect to the intervertebral cage 210 so as to expand and angularlyadjust the intervertebral cage 510 in the manner described above withrespect to the cage 210. In addition, the upper and lower plates 520 and540 may be connected with elastic springs 530 to control the relativemovement of the plates 520 and 540 in the manner described above. Thesprings 530 can be configured geometrically as elastically deformablestrips 530, or can be alternatively configured as desired.

As shown in FIG. 5B, when the intervertebral cage 510 is in itscompressed, insertion configuration, the wedges 550 and 551 are in theirinitial configuration. As shown in FIG. 5C movement of the first wedge550 toward the second wedge 551 along the guide rail 548 causes theupper plate 520 to move away from the lower plate 540 along thetransverse direction (expansion), and further causes the first portionof the upper plate 520 to move relative to the second portion of theupper plate 520 away from the lower plate 540 along the transversedirection, thereby angularly adjusting the intervertebral cage 510. Asshown in FIG. 5D, movement of the second wedge 551 toward the firstwedge 550 along the guide rail 548 causes the upper plate 520 to moveaway from the lower plate 540 along the transverse direction T(expansion), and further causes the second portion of the upper plate520 to move relative to the first portion of the upper plate 520 awayfrom the lower plate 540 along the transverse direction, therebyangularly adjusting the intervertebral cage 510. Subsequent movement ofthe other of the first and second wedges 550 and 551 can return the cage210 to its first relative angular orientation.

The elastic springs 530 can apply a force against the plates 520 and 540that resists but allows movement of the upper plate 520 relative to thelower plate 540. The springs 530 can be configured such that free endsof the spring 530 connect the upper plate 520 to the lower plate 540,with no free ends of the spring 530 that are loose and unattached. Forinstance, one end of the spring 530 can attach to the lower plate 540,and the other end of the spring 530 can attach to the upper plate 520.The intervertebral cage 510 may be particularly advantageous when 3Dprinted in one run in a metal such as a titanium.

FIGS. 6A to 6F illustrate yet still another example of an expandable andangularly adjustable intervertebral cage 610 of the present disclosurewhich utilizes many of the same features of the example described above.As shown, the cage 610 can include a housing 612 that, in turn, includesan upper housing portion 619 and a lower housing portion 639. The upperhousing portion 619 can include an upper plate 620 and upper sidewalls624 that extend down from the upper plate 620 along the transversedirection T. The lower housing portion 639 can include a lower plate 640and lower sidewalls 644 that extend up from the lower plate 640 alongthe transverse direction T. The intervertebral cage 610 can furtherinclude a pair of wedges 650 and 651 that translate on a guide rail 648located on an inner transverse surface of the lower plate 640, and canmove in a manner as described above for intervertebral cage 210.However, as an alternative or in addition to including spring membersconfigured as elastically deformable strips, the cage 610 can include analternative spring member 630 that resists but allows movement of thecage 610. For instance, in one example, the cage 610 an include thespring 630 configured as a resilient lattice structure 631. The latticestructure 631 can be configured as a honeycomb-like screen 630. Thespring member 630 can further define sides of the intervertebral cage610 that extend from the upper plate 620 to the lower plate 640 and arespaced from each other along the lateral direction A.

The housing 612 can include a pair of wedges 650 and 651 that translateon a guide rail 648 located on a transverse inner surface of the lowerplate 640, and move in a manner as described above with respect to theintervertebral cage 210. One or both of the upper plate 620 and thelower plate 640 can include a porous structure as described above withrespect to cage 410. For instance, the upper plate 620 can include aporous structure 622 that at least partially define the upper bearingsurface. Further, the lower housing portion 639 can include a porousstructure 642 that defines the lower bearing, as shown in FIGS. 6D and6E. Further, one or both of the upper and lower plates 620 and 640 caninclude teeth 646 configured to grip the respective vertebral endplate.One or both of the wedges 650 and 651 can define aninstrument-engagement member that is configured to couple to an actuatorthat, in turn, is configured to move one or both of the wedges 650 and651 to expand and/or angulate the intervertebral cage 610. In oneexample, the instrument-engagement member can be configured as aninstrument-engaging opening 652 that is configured to receive anactuator and insertion instrument 690, as shown in FIG. 6B. The actuatorand insertion instrument 690 can be configured to insert the cage 610into the intervertebral space, and can further actuate the cage 610 fromits first or insertion configuration to its second or expandedconfiguration in the manner described above. Further, the instrument 690can cause the cage 610 to angulate in the manner described above. Inparticular, the actuation of each of the wedges 650 and 610 fortranslation towards the other of the wedges 650 and 651 can be achievedin the manner previously described above.

It is contemplated that the present embodiment may be particularlyuseful for achieving both distraction and angulation in the coronalplane, using one device. The cage 610 may be effective to restoresagittal balance, while still being less invasive, and due to itsability to be angulated in the coronal plane, is effective for treatingdegenerative scoliosis or to correct other coronal plane abnormalities.The cage 610 of the present disclosure can achieve these dual goals byproviding two independently movable wedges 650 and 651 from the first orinsertion configuration illustrated in FIGS. 6F-6G, in which the springmember 630 can be in a relaxed configuration. That is, the latticestructure 631 of the spring 630 can be relaxed and thus not apply aforce to either of the upper and lower plates 620 and 640. The wedges650 and 651 may be moved by the same amount, to distract, as shown inFIGS. 6H-6I. As illustrated in FIGS. 6H and 6I, when the intervertebralcage is in the second or expanded configuration with the second relativeangular orientation equal to the first relative angular orientation, thelattice structure 631 of the spring 630 can be placed in tension alongthe transverse direction T. Thus, the lattice structure 631 applies acompressive force to the upper and lower endplates 620 and 640 along thetransverse direction T that biases the upper and lower endplates 620 and60 toward each other. The wedges 650 and 651 overcome the force as theymove the cage 610 to the expanded configuration. Alternatively oradditionally, referring now to FIGS. 6J-6K, one of the wedges 650 and651 may be moved only to effect angulation only, or both wedges 650 and651 may be moved a disproportionate amount so that there is bothdistraction and angulation.

When the cage 610 is angulated, one longitudinal end of the latticestructure 631 can be placed in tension greater than the otherlongitudinal end of the lattice structure 631. The other longitudinalend of the lattice structure 631 can be placed in compression or lessertension, or can otherwise be neutral. Generally speaking, the amount ofheight increase or expansion of the cage 610 along the transversedirection T can be dependent on the implant height. In some embodiments,the expansion may be in the range of up to approximately 5 mm.Angulation can be in the range from about 0 degrees up to approximately16 degrees, including from approximately 0 degrees to approximately 8degrees.

As mentioned above, the intervertebral cages of the present disclosureare configured to be able to allow insertion through a narrow accesspath, but are able to be expanded and angularly adjusted so that thecages are capable of adjusting the angle of lordosis of the vertebralsegments. By being able to angularly adjust and expand (or distract),the cages allow a very narrow anterior for insertion and a largeranterior after implantation to accommodate and adapt to larger angles oflordosis or kyphosis. Additionally, the cages can effectively restoresagittal balance and alignment of the spine, and can promote fusion toimmobilize and stabilize the spinal segment.

With respect to the ability of the expandable cages to promote fusion,many in-vitro and in-vivo studies on bone healing and fusion have shownthat porosity can facilitate vascularization, and that the desiredinfrastructure for promoting new bone growth should have a porousinterconnected pore network with surface properties that are optimizedfor cell attachment, migration, proliferation and differentiation. Atthe same time, it is believed that cage's ability to provide adequatestructural support or mechanical integrity for new cellular activity isanother primary factor for achieving clinical success. Regardless of therelative importance of one aspect in comparison to the other, what isclear is that both structural integrity to stabilize, as well as theporous structure to support cellular growth, can assist in proper andsustainable bone regrowth.

The cages described herein can further take advantage of currentadditive manufacturing techniques that allow for greater customizationof the devices by creating a unitary body that may have both solid andporous features in one. In some embodiments as shown, the cages can havea porous structure, and be made with an engineered cellular structurethat includes a network of pores, microstructures and nanostructures tofacilitate osteosynthesis. For example, the engineered cellularstructure can comprise an interconnected network of pores and othermicro and nano sized structures that take on a mesh-like appearance.These engineered cellular structures can be provided by etching orblasting to change the surface of the device on the nano level. One typeof etching process may utilize, for example, HF acid treatment. Thesesame manufacturing techniques may be employed to provide these cageswith an internal imaging marker. For example, these cages can alsoinclude internal imaging markers that allow the user to properly alignthe cage and generally facilitate insertion through visualization duringnavigation. The imaging marker shows up as a solid body amongst the meshunder x-ray, fluoroscopy or CT scan, for example. The cages describedherein can comprise a single marker, or a plurality of markers. Theseinternal imaging markers greatly facilitate the ease and precision ofimplanting the cages, since it is possible to manufacture the cages withone or more internally embedded markers for improved visualizationduring navigation and implantation.

Another benefit provided by the implantable devices of the presentdisclosure is that they are able to be specifically customized to thepatient's needs. Customization of the implantable devices is relevant toproviding a preferred modulus matching between the implant device andthe various qualities and types of bone being treated, such as forexample, cortical versus cancellous, apophyseal versus central, andsclerotic versus osteopenic bone, each of which has its own differentcompression to structural failure data. Likewise, similar data can alsobe generated for various implant designs, such as for example, porousversus solid, trabecular versus non-trabecular, etc. Such data may becadaveric, or computer finite element generated. Clinical correlationwith, for example, DEXA data can also allow implantable devices to bedesigned specifically for use with sclerotic, normal, or osteopenicbone. Thus, the ability to provide customized implantable devices suchas the ones provided herein allow the matching of the Elastic Modulus ofComplex Structures (EMOCS), which enable implantable devices to beengineered to minimize mismatch, mitigate subsidence and optimizehealing, thereby providing better clinical outcomes.

A variety of spinal implants may be provided by the present disclosure,including interbody fusion cages for use in either the cervical orlumbar region of the spine. Further, it is contemplated that theprinciples of this disclosure may be utilized in a cervical interbodyfusion (CIF) device, a transforaminal lumbar interbody fusion (TLIF)device, anterior lumbar interbody fusion (ALIF) cages, lateral lumbarinterbody fusion (LLIF) cages, posterior lumbar interbody fusion (PLIF)cages, and oblique lumbar interbody fusion (OLIF) cages.

It should be appreciated that the illustrations and discussions of theembodiments shown in the figures are for exemplary purposes only, andshould not be construed limiting the disclosure. One skilled in the artwill appreciate that the present disclosure contemplates variousembodiments. Additionally, it should be understood that the conceptsdescribed above with the above-described embodiments may be employedalone or in combination with any of the other embodiments describedabove. It should be further appreciated that the various alternativeembodiments described above with respect to one illustrated embodimentcan apply to all embodiments as described herein, unless otherwiseindicated.

What is claimed is:
 1. An expandable intervertebral cage, comprising: anupper housing portion having an upper plate and upper sidewalls thatextend out from the upper plate, wherein the upper plate defines anupper bearing surface configured for placement against an endplate of afirst vertebral body; a lower housing portion having a lower plate andlower sidewalls that extend out from the lower plate, wherein the lowerplate defines a lower bearing surface configured for placement againstan endplate of a second vertebral body, wherein the upper and lowersidewalls are configured to slide along each other; an expansion andangular adjustment mechanism disposed between the upper and lowerplates, and configured to effect height and angular adjustment of theintervertebral cage, the expansion and angular adjustment mechanismcomprising 1) a pair of wedges located at opposite ends of the housing,each wedge having upper and lower engagement surfaces configured engagerespective engagement surfaces of the upper and lower sidewalls, and 2)a driver component connecting the wedges together and configured to movethe wedges toward each other upon actuation of the driver component,thereby causing the engagement surfaces of the wedges to bear againstthe engagement surfaces of the sidewalls, thereby moving the upper andlower bearing surfaces away from each other, wherein a load applied toan end of the cage causes the upper plate to angulate relative to thelower plate.